Firestik Antenna FireStik MU8R18 18-Foot Single Antenna Coaxial Cable Stranded center conductor to maximize flexibility and prevent untimely breakage. Shielding coverage that averages 95% to protect against RF leaks and interferrence. Polyvinyl center insulation for ruggedness and longevity. Performance that exceeds mil-spec requirements for 50 ohm RG-58A/U coax.